Why did Avraham not take the youths with him to witness the Akeidah?
Seforno: Because he was afraid that they would object or disturb him in some other way as he sacrificed Yitzchak.
What did Avraham mean when he said to them, "We will go until Koh"?
Rashi #1: He was telling the youths that he and Yitzchak only had a little further to go, and then they would return.
Rashi #2 and Targum Yonasan: He was pondering what would happen to HaSh-m's promise "So (Koh) will be your children (like the stars)!" (15:5).
Considering that Avraham intended to sacrifice Yitzchak, how could he tell them that they would return?
Rashi: This was a prophecy that Yitzchak would return together with him, even though he himself did not realize it.
Why are the youths (Yishmael and Eliezer) equated to the donkey?
Rosh, from Bereishis Rabah 56:1: Avraham and Yitzchak saw the Shechinah over the mountain. The youths did not see anything, like the donkey. 1
Maharal (Gevuros Hashem Ch. 44, p. 166): This is the Halachic source that an Eved, like a Chamor, has no pedigree [paternity]. Chamor represents Chomer that is put into motion by a Tzurah, just as donkey transports its rider, and the temporal Eved is subservient to an Adon. 2
Hadar Zekenim says similarly.
In Maharal's thought, Chomer is raw material, or potential, and Tzurah is what actualizes that potential. To illustrate, the iron from which a knife is made is its Chomer, and the sharp edge is its Tzurah. So too, the Adon directs the Eved towards a purpose; also refer to 22:3:2.1:1***. Also see Maharal (Gevuros Hashem Ch. 4, p. 31). (EK)
